It's an exciting time in the world of HTML as the W3C (World Wide Web Consortium) is hard at work on the latest version of HTML – 5.0.
This version of HTML is being developed by the WHATWG (Web Hypertext Application Technology Working Group), whose stated goal is to continue evolution of the web. Since they're designing HTML 5 with web developers in mind, they've included several features that will make our lives much easier.
One example is the new doctype tag. In HTML 4, the doctype tag looks something like this:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
In HTML 5, the doctype tag looks like this:
… which is far easier to remember. HTML 5 has also streamlined the character set definition code. Here's the old way:
<meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1">
… and here's the HTML 5 way:
Again, the new version is much easier to remember.
HTML 5 has a number of new tags designed to assist with layout. Most designers use div tags to lay out their pages, giving them names to keep the sections distinct, which usually results in dozens of nested div tags all over the page. The new HTML has tags like <section>, <header>, <footer>, and <nav> to break the page into clearly defined parts. It's helpful for web developers but even better for users with accessibility software, which can easily bog down when describing a page held together with dozens of div tags.
HTML 5 finally does away with several tags that have long been deprecated (and which you are hopefully not using anyway!) Examples are all the old frame tags (<frame>,<frameset> and <noframes>) as well as all the formatting tags whose functions are best handled through CSS (<font>, <center>, <basefont>, <big>, etc.). A number of formatting attributes are also gone (align, background and bgcolor on the <body> tag, most of the table formatting attributes like border, height and width, etc.). If you haven't already cleared these items from your sites, now would be the time.
The WHATWG editors estimate that HTML 5 probably won't complete all the W3C's steps towards recommendation until 2022 at the earliest. Don't panic – that doesn't mean you can't use HTML 5 long before that! In fact, you can start revising and developing your sites for HTML 5 immediately. The latest versions of Opera, Safari and Internet Explorer have partial support for 5's new feature set, notably the <canvas> tag. For an up to date list of which browsers support which features, check out the WHATWG wiki page "Implementations in Web Browsers," located at http://wiki.whatwg.org/wiki/Implementations_in_Web_browsers.